Rotary piston machine

ABSTRACT

A rotary piston is eccentrically mounted in a housing and comprises chamber-defining means, which define a plurality of fluid-handling chambers with said housing. The chamber-defining means comprise sealing means in sealing surface contact with said housing to seal said fluid-handling chambers from each other. The sealing means are arranged to derive from the pressure of fluid in said fluid-handling chambers and from the centrifugal force which is due to the rotation of said rotary piston a first force urging said sealing means against said housing. The chamberdefining means further comprise force-deriving means for deriving from said pressure of fluid in said fluid-handling chambers a second force which throughout the revolution of said rotary piston is smaller than and opposes said first force. The housing is formed with first and second fluid ports, which are peripherally spaced apart and each of which is adapted to connect each of said fluid-handling chambers to the outside of said housing once during each revolution of said piston.

United States Patent Nebel [54] ROTARY PISTON MACHINE [72] Franz P. Nebel, Muhlberg 11,

A5132 Geretsberg, Austria Filed: May 19, 1970 Appl. No.: 38,845

Inventor:

Field of Search ..418/268, 270, 145, 146, 147, 418/148, 253, 269, 29

References Cited UNITED STATES PATENTS 8/ 1963 Eickmann ..418/26.8 X 5/1932 Olson ....41 8/268 1,093,005 4/ 1914 Myers ..4l8/269 3,190,074 6/1965 Johns ..418/29 FOREIGN PATENTS OR APPLICATIONS 12,259 5/1891 Great Britain ..4l8/145 [451 Sept. 5, 1972 Primary Examiner-Carlton R. Croyle Assistant Examiner--Richard E. Gluck Attorney-Otto John Munz 7] ABSTRACT A rotary piston is eccentrically mounted in a housing and comprises chamber-defining means, which define a plurality of fluid-handling chambers with. said housing. The chamber-defining means comprise sealing means in sealing surface contact with said housing to seal said fluid-handling chambers from each other. The sealing means are arranged to derive from the pressure of fluid in said fluidhandling chambers and from the centrifugal force which is due to the rotation of said rotary piston a first force urging said sealing means against said housing. The chamber-defining means further comprise force-deriving means for deriving from said pressure of fluid in said fluid-ham dling chambers a second force which throughout the revolution of said rotary piston is smaller than and opposes said first force. The housing is formed with first and second fluid ports, which are peripherally spaced apart and each of which is adapted to connect each of said fluid-handling chambers to the outside of said housing once during each revolution of said piston.

2 Claims. 6 Drawing Figures PATENTEBSEP Sum INVENTOR:

FRANZ P. NEBEL ATTORNEY ROTARY PISTON MACHINE This invention relates to rotary piston machines for use with liquids and gases and for use as prime movers and for performing work, particularly to such machines which comprise a housing in which means which act as an rotary piston and define fluid-handling chambers are eccentrically mounted.

The known machines of this type comprise linear seals so that high contact pressures are produced at the sliding surfaces even when the machines is operated under a relatively lowpressure. These high contact pressures at the sliding surfaces result in an undesired generation of large quantities of heat.

This disadvantage is eliminated according to the present invention in that all sealed joints between the suction and discharge sides of the pump or between the inlet and outlet sides of machine for performing work comprise surface seals. Thereby, the contact pressures between the sliding surfaces of the housing and piston will have very low values even when the pump or the machine is operated under a very high pressure.

The subject matter according to the invention is shown by way of example on the drawing, in which FIGS. 1 and 2, respectively, are an end view and a sectional view showing a fuel injection pump.

FIG. 3 represents the determination of the contact pressure at the sealing surfaces of the piston and cylinder.

FIG. 4 illustrates the continuous change of the delivery rate.

FIG. 5 is a sectional view showing the machine for use as a compressor.

FIG. 6 is a sectional view showing the machine for use as a prime mover operable by gaseous fluids.

The fuel injection pump shown in FIGS. 1 and 2 was designed to meet an urgent economic requirement for a pump which can be manufactured easily at a low cost and nevertheless, this pump has a high capacity and can be used as an injection type pump for motor fuel and fuel oil. Fuel injection pumps are commercially important because there is a trend to replace fuel injection pumps for carburetors in fuel engines and the demand for motor vehicles increased throughout the world. The fuel injection pumps which are now available are highly expensive so that an inexpensive structure is urgently desired.

FIGS. 1 and 2 show a pump according to the present invention which is extremely simple because the essential parts of the pump may be made at a low cost by a precision stamping process.

The fuel injection pump consists mainly of a chamber-like housing 1, two end covers 2 and 3 on the housing, a rotor4 to which shoelike vanes 7 are linked by links 6, and a rotatably mounted shaft 5 for supporting the rotor.

Mode of operation:

During rotation of the rotor 4, the shoelike vanes 7 are linked to the rotor 4 by links 6. Thelinks are urged by centrifugal force against the inside wall of the housing 1 so that the suction chamber R/s and the pressure chamber R/d that are formed owing to the eccentric mounting of the shaft 5 are constantly sealed from each other. The suction produced in the chamber R/s sucks the fluid to be handled through the suction port S. The fluid is subsequently discharged from the pressure chamber R/d into the discharge port D.

The contact pressure between the sliding surfaces of the housing and the vanes 7 will be minimized even when the pump discharges fluid under a very high pressure. As shown in FIG. 3, the ratio of the radius r, of the shoelike vane to the radius r of the link 6 is in a suitable range so that a torque is produced by the centrifugal force. This force is due to the masses of the links 6 and vanes 7 and the radially outwardly directed pressure that is exerted by the fluid being handled on the vanes which torque is opposed by an oppositely directed torque. This opposite torque is due to the radially inwardly directed pressure acting on the links 6. The difference between the inwardly directed torque and the somewhat higher, outwardly directed torque determines the contact pressure between the sliding surfaces of the vanes 7 and the inside surface of the housing.

FIG. 4 shows diagrammatically how the delivery rate of the pump may be continuously varied from zero to a maximum for both handling directions by a change of the eccentricity of the shaft 5 without any change in the speed and direction of rotation of the pump. For instance, the shaft 5 is mounted in partly open bearing plates 8, which are mounted on an axis 0 for a pivotal movement through the angle H. Both end covers are formed with slots L to permit the pivotal movement of the shaft. The bearing housings are pivotally movable by means of a rodlike element 9. Other means for adjusting the shaft are not described because they are known in the art.

The pivotal connections between the rotor 4, links 6 and vanes 7 comprise preferably open hinge eyes so that these elements can simply be inserted into assembled position. The tensile action will result in a clearance-free seal even when there is a substantial bearing clearance in the hinged eyes.

Because the delivery rate can be continuously controlled, the pump of FIG. 3 may also be used as hydraulic pump. A hydraulic transmission will be provided if a pump according to the invention is connected by suita ble conduits to one or more motors. I

FIG. 5 represents a compressor according to the invention.

The compressor consists mainly of a housing 10, a rotor 11, to which a shoelike vanes 14 are linked by links 13, and a shaft 12.

The function is the same as that described with reference to FIGS. 1, 2 and 3 but the movable elements are designed so that the volume of the handling chamber R has been reduced to zero when the corresponding vane is in the position in which it has the smallest radius.

FIG. 6 according to the invention shows a rotary piston motor operable by gaseous fluids. This motor is basically similar to the machines shown in FIGS. 1 to 5 and mainly comprises a housing 15, a rotor 16 fixed to a shaft 17, and shoelike vanes 19 linked to the rotor 16 by links 18.

The two chambers M which are temporarily formed during each revolution of the rotor do not communicate with the fluid-handling chamber A but are connected to each other by an annular duct K so that they do not act as clearance spaces.

The fluid which is supplied through the pressure pipe Z exerts on the rotor 16 that is provided with the links 18 and the vanes 19, a torque in the direction of the arrow. This torque is due to a small torque-deriving surface that is available even in the initial position shown in the drawing owing to the eccentric position of the rotor shaft 17. During the movement of a vane 19 from its initial position at Z to the position in which the exhaust of the fluid begins, the torque-deriving surface and with it the fluid-handling chamber are increased so that the force acting on the position and the output power remain constant in spite of the decrease in pres sure due to the expansion of the motive fluid. The torque remains substantially constant throughout the revolution of the shaft 17. This is in contrast, e.g., to a steam engine that has a reciprocating piston, where the force on the piston and with it the power delivered by the piston decrease as the steam expands during the working stroke whereas the power deriving piston surface remains constant.

What is claimed is:

1-. A rotary piston machine, arranged as a prime mover, comprising a housing having walls to form an enclosed rotor space;

a rotary piston being eccentrically mounted in said housing and including chamber-defining means, which define a plurality of fluid-handling chambers within said housing, and a rotor mounted on a shaft for rotation;

said chamber-defining means including sealing means in sealing surface engagement with said housing to seal said fluid-handling chambers from each other;

said sealing means being arranged to derive from the pressure of fluid in said fluid-handling chambers and from the centrifugal force which is due to the rotation of said rotary piston, a first force urging said sealing means against said housing;

said chamber-defining means further including force-deriving means for deriving from said pressure of fluid in said fluid-handling chambers a second force which throughout the revolution of said rotary piston within a predetermined speed range is smaller than and opposes said first force,

said force-deriving means being pivotally linked to said rotor and to the sealing means, and said housing being formed with first and second fluid ports, which are peripherally spaced apart and each of which is adapted to connect each of said fluid-handling chambers to the outside of said housing once during each revolution of said piston, said chamber-defining means being adapted to define first and second secondary chambers and to 2. A rotary piston machine, arranged to be operable as a compressor, comprising a housing having walls to form an enclosed rotor space;

a rotary piston being eccentrically mounted in said housing and including chamber-defining means, which define a plurality of fluid-handling chambers within said housing, and a rotor mounted on a shaft for rotation' said chamber-defining means including sealing means in sealing surface engagement with said housing to seal said fluid-handling chambers from each other;

said sealing means being arranged to derive from the pressure of fluid in said fluid-handling chambers and from the centrifugal force which is due to the rotation of said rotary piston, a first foroe urging said sealing means against said housing;

said chamber-defining means further including force-deriving means for deriving from said pressure of fluid in said fluid-handling chambers a second force which throughout the revolution of said rotary piston within a predetermined speed range is smaller than and opposes said first force;

said force-deriving means being pivotally linked to said rotor and to the sealing means, and said housing being formed with first and second fluid ports, which are peripherally spaced apart and each of which is adapted to connect each of said fluid handling chambers to the outside of said housing once during each revolution of said piston,

said chamber-defining means being arranged to reduce each of said fluid-handling chambers to zero volume once during each revolution of said piston. 

1. A rotary piston machine, arranged as a prime mover, comprising a housing having walls to form an enclosed rotor space; a rotary piston being eccentrically mounted in said housing and including chamber-defining means, which define a plurality of fluid-handling chambers within said housing, and a rotor mounted on a shaft for rotation; said chamber-defining means including sealing means in sealing surface engagement with said housing to seal said fluidhandling chambers from each other; said sealing means being arranged to derive from the pressure of fluid in said fluid-handling chambers and from the centrifugal force which is due to the rotation of said rotary piston, a first force urging said sealing means against said housing; said chamber-defining means further including force-deriving means for deriving from said pressure of fluid in said fluidhandling chambers a second force which throughout the revolution of said rotary piston within a predetermined speed range is smaller than and opposes said first force, said force-deriving means being pivotally linked to said rotor and to the sealing means, and said housing being formed with first and second fluid ports, which are peripherally spaced apart and each of which is adapted to connect each of said fluid-handling chambers to the outside of said housing once during each revolution of said piston, said chamber-defining means being adapted to define first and second secondary chambers and to seal said secondary chambers from said fluid-handling chambers throughout the revolution of said piston, and to vary the volumes of said secondary chambers in mutually opposing senses during the revolution of the piston; said piston formed with duct means connecting said first and second secondary chambers.
 2. A rotary piston machine, arranged to be operable as a compressor, comprising a housing having walls to form an enclosed rotor space; a rotary piston being eccentrically mounted in said housing and including chamber-defining means, which define a plurality of fluid-handling chambers within said housing, and a rotor mounted on a shaft for rotation; said chamber-defining means including sealing means in sealing surface engagement with said housing to seal said fluid-handling chambers from each other; said sealing means being arranged to derive from the pressure of fluid in said fluid-handling chambers and from the centrifugal force which is due to the rotation of said rotary piston, a first force urging said sealing means against said housing; said chamber-defining means further including force-deriving means for deriving from said pressure of fluid in said fluid-handling chambers a second force which throughout the revolution of said rotary piston within a predetermined speed range is smaller than and opposes said first force; said force-deriving means being pivotally linked to said rotor and to the sealing means, and said housing being formed with first anD second fluid ports, which are peripherally spaced apart and each of which is adapted to connect each of said fluid handling chambers to the outside of said housing once during each revolution of said piston, said chamber-defining means being arranged to reduce each of said fluid-handling chambers to zero volume once during each revolution of said piston. 